The present invention relates to an electronic apparatus or device with a battery power source contained therein, in which a rechargeable battery and customary cylindrical dry batteries can be replaced with each other. This invention is suitable, although not exclusively, for application to radio communication devices for a mobile telecommunication system to improve their usability.
Many portable electronic apparatuses or devices have therein batteries as a power source, and are designed such that a rechargeable battery and dry batteries can be replaced with each other. One example of such electronic apparatus is a portable cordless telephone. An essential portion of a conventional cordless telephone will be described with reference to FIGS. 6 and 7.
FIG. 6 shows a battery mounting portion of the cordless telephone with parts thereof in cross section. Illustrated in this figure is a condition that a rechargeable battery is mounted. In the figure, reference numeral 1 denotes a housing of the cordless telephone, in which the battery mounting portion is formed integrally on the rear of the housing. A rechargeable battery pack 2 mounted therein has an outer casing 2a which is made of a plastic material. A plurality of rechargeable battery cells are accommodated in this casing. The battery cells are connected to one another through metal pieces, thus forming a battery unit 2b. Electrode contacts 2c are provided on a rear portion of the casing 2a and connected to the battery unit 2b. Contacts 3 for supplying electric power to an internal circuit (not shown) of the cordless telephone are fixed on the bottom of the battery mounting portion 1a (upper in the drawing) by means of screw fastening or thermal caulking. Reference numeral 4 denotes a cover of the battery mounting portion, which is engaged with the housing 1 to hold the battery pack 2.
On the other hand, FIG. 7 shows the battery mounting portion 1a in a state that customary cylindrical dry batteries, such as AAA-size dry batteries, are mounted in place of the rechargeable battery pack 2. In FIG. 7, reference numeral 5 denotes a dry-battery power source pack. The power source pack 5 includes an attachment holder 5a made of a plastic material, in which a plurality of dry batteries 6 are accommodated. The holder 5a has conical coil springs 5b which contact with minus electrodes of the respective dry batteries 6 and exert contact pressures on them, and terminals 5c which contact with plus electrodes of the dry batteries. Further, contacts 5d are provided on the holder 5a at substantially the same positions as the contacts 2c of the rechargeable battery pack 2 shown in FIG. 6, and serve as power output terminals of the dry batteries 6. The attachment holder 5a is formed in substantially the same shape as the outer casing 2a of the rechargeable battery pack 2 to be compatible with the battery pack 2. When the rechargeable battery pack 2 is attached in the battery mounting portion 1a, as shown in FIG. 6, the contacts 2c of the battery pack 2 contact with the respective contacts 3 on the battery mounting portion side, and electric power is supplied to the internal circuit (not shown) of the cordless telephone. Then, the cover 4 is engaged with the housing 1 to prevent the rechargeable battery pack 2 from dropping when the cordless telephone is used or carried. The dry-battery power source pack 5 is attached to the cordless telephone in place of the rechargeable battery pack 2 as shown in FIG. 7 and can be used during an emergency, for example, when power of the battery pack 2 is exhausted and it can be used no longer.
However, in order to use the dry-battery power source pack 5 during an emergency in the above-described manner, it is necessary to carry the power source pack 5 or at least the holder 5a in addition to the cordless telephone. Carrying the power source pack 5 or the holder 5a is troublesome, and there is a risk that they will be lost or broken.